Justin Alexander Casquejo allegedly slipped past four layers of WTC security and spent two hours atop the tallest building in the United States, until he was finally discovered by a construction worker. Photo: Facebook

Manhattan prosecutors plan to take a long, careful look at the kid who admits he breezed past security to climb to the top of the new Freedom Tower before they decide how to proceed with his case.

Justin Casquejo, 16, will undergo an in-depth “youth assessment” by court mental-health personnel before officials recommend what the outcome of his case should be, the boy was told at his first court appearance Wednesday.

In a shocker first reported in The Post, the thrill-seeking Casquejo made his way past a chain-link fence and a sleeping guard last month en route to the tower’s spire atop the 104th floor.

On Wednesday, the normally chatty teen declined to comment at Midtown Community Court on 54th Street.